Effects of varying flux and transmembrane pressure conditions during ceramic ultrafiltration on the infectivity and retention of MS2 bacteriophages

.Membrane ultrafiltration (UF) constitutes a promising technology to remove viruses including phages from water. However, the removal efficiency of viruses such as MS2 phages strongly depends on operational parameters, such as flux and transmembrane pressure (TMP) conditions during UF. Initially, we investigated during this lab-scale study if the infectivity of MS2 phages was impaired at very high fluxes and the associated high TMPs during ceramic membrane UF The ratio of plaque forming units (PFU) indicating infectious MS2 phages and the total amount (infectious and non-infectious) of MS2 phages measured via digital polymerase chain reaction (dPCR) remained constant at varying fluxes. Hence, we concluded that the infectivity of MS2 phages was not significantly affected. Secondly, a trend analysis of PFUs and dPCR results during varying flux/TMP. conditions was performed. It was found that with increasing fluxes/TMPs, the retention of MS2 phages significantly increased Enhanced aggregation of the MS2 phages was expected to improve the size exclusion effect during ceramic UF while enlargement of ceramic membrane pores could be ruled out. Our findings partially contradict investigations with polymeric UF membranes. Possible underlying mechanisms were comprehensively discussed.

Automated summary

This study investigated the infectivity of MS2 phages at high fluxes and associated transmembrane pressures (TMPs) during ceramic membrane ultrafiltration (UF). The results showed that the infectivity of MS2 phages was not significantly affected by high fluxes and TMPs. The retention of MS2 phages increased with increasing fluxes and TMPs in ceramic UF, likely due to enhanced aggregation.